This invention generally relates to systems used in temperature maintenance, and specifically to a segmented liner system having compartments containing microencapsulated phase change material.
The use of phase change material to maintain the temperature of items within containers is well known in the art. For cooling applications, phase change materials are chosen for their low melting points, high heat of fusion, and capacity to store large amounts of heat energy. The microencapsulation of phase change materials (PCMs) provides for preferably plastic casings to enclose small particles of PCM, and allows easier handling of the material, and increases the range of applications where the materials can be used in temperature regulation or maintenance. The use of microencapsulated PCM in a liner assembly enables the system to absorb more heat energy, and thus prolong the cooling effect.
Many designs exist that consist of a double-wall container system with provisions to maintain the temperature of items stored within. The double-wall feature creates an interstitial space, and the interstitial space can be either filled with PCM, or can contain an integral or removable liner member filled with PCM. These designs can also include an exterior insulation layer. This type of double-wall container is relatively complex and expensive to manufacture, and the utility is somewhat limited in application. With most double wall designs in a cooling application, the entire container or a bulky liner is required to be precharged in the freezer, taking up valuable storage space. Other designs for thermal containers use one or more separate, removable pouches, sacks, or bricks, used as interior gel packs, containing PCMs. These can be placed on the interior side of the container, surrounding the item to be cooled. However, such direct contact is not always feasible where it is necessary for the item being heated or cooled to be isolated, out of direct contact with the gel packs. For example, a user may require that food being served at a picnic or potluck not be in direct contact with one or more gel packs, and would prefer using a double-wall container with PCM liner.
Normally, gel packs are rigid pouches in their frozen state, and the large packs cannot be easily bent to conform to a curved container surface, such as a standard bowl. Food serving applications can often employ containers with concave, curved surfaces, making it more difficult to provide proper contact between the container surfaces and the traditional gel pack. In addition, it is difficult to adequately cover substantially the entire curved bowl surface with a series of rectangular gel packs. In such an application, there is a need for a flexible, segmented, removable liner system which may be used in-between nested, curved containers. There is a further need to augment the temperature maintenance of such containers with a top cover which also employs a segmented liner with microencapsulated PCM.